Return mechanism for swivels



Oct. 22, 1963 M. P. BURKE v RETURN MECHANISM FOR sums 3 Sheets-Sheet 1 Filed Bay 24, 1962 INVENTOR. (/IP/CEEBUE/(E Z mu(%w 147' TOPIVEYS'.

Oct. 22, 1963 M. P. BURKE RETURN MECHANISM FOR SWIVELS 3 Sheets-Sheet 2 F260 60 Filed May 24, 1962 INVENTOR. Mqae/cs R Bale/ 5 Oct. 22, 1963 Filed May 24, 1962 .RETURNIIECH'ANISIIFORSWIVELS' P. BURKE 3,107,891

I 3 Sheets-Sheet 3 INVENTOR. 75 Mame/c2:- R Buses United States Patent 3,197,891 RETURN lviECHANISM FGR SWIVEL?) Ilit'aurice I. Burke, Burke inc, 514%) N. Westmoreland Road, Dallas, Tex. Filed May 24, 1962, Ser. No. Ziltldlld 6 Claims. (Cl. 248-417) This invention relates to a return mechanism for swivels, as, for example, swivels used for chairs.

An object of the present invention is to provide a new return mechanism for a swivel that, despite its simplicity, provides all of the desired functions of such a device. Thus, it is possible repeatedly to move the swivel full circle in one direction without winding up the mechanism. The biasing force is never so large as to preclude easy movement by the user, yet adequate at all times to return the swivel to a stable, fixedly defined orientation.

Another object of this invention is to provide a new, two-part swivel pedestal or support incorporating simple means, whereby, without any physical alteration at all, a return mechanism can selectively be incorporated.

This application is a continuationin-part of my prior application Serial No. 81,788, filed January 10, 1961, now abandoned, and entitled, Return Mechanism for Swivels.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several embodiments of the invention. For this purpose, there are shown a few forms in the drawings accompanying and forming part of the present specification, and which drawings, unless as otherwise indicated, are true scale. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a vertical sectional view of a two-part swivel pedestal incorporating the present invention;

FIG. 2 is a vertical sectional view showing in detail, and on an enlarged scale, the pedestal surbase at which the return mechanism is located;

FIGS. 3 and 4 are enlarged transverse sectional views, taken along planes indicated by lines 33 and 4-4 of FIG. 1, and illustrating the respective parts of the pedestal at the area of juxtaposition;

FIG. 5 is a sectional view, taken along plane corresponding to line 55 of FIG. 2, and illustrating one of the bearing structures;

FIG. 6 is a vertical fragmentary sectional view of a two-part pedestal showing a modified fonm of the present invention;

FIGS. 7 and 8 are sectional views, taken along planes correspondin to lines 7-5 and '8% of FIG. 6;

FIG. 9 is an axial sectional view of the race-forming insert itself; and

FIGS. 10, 11 and 12 are, respectively, views similar to FIGS. 6, 8 and 9, but showing a still further modified form of the present invention.

In FIG. 1 there is illustrated a pedestal 19 that may be made of cast aluminum or the like. The edestal 1'23 comprises a lower part 11 and an upper part 12 separated from each other at a horizontal plane A, yet connected together for relative rotation about the vertical axis 13 of the pedestal, in a manner hereinafter to be described.

The upper part 12 is generally hollow and forms the surbase of the pedestal, flaring outwardly in the upward direction to provide at its top a circular flange 14- (PEG. 2) upon which the supported structure, in this instance 3, l 13M Patented Get. 22, 1963 a seat 15, rests. In the present instance, the flange has a series of apertures 16 through which fastening'screws 17 extend. The upper part 12 is generally frusto-conical in external contour, terminating at its lower end in a circular undersurface 12a. The vertical dimension of the upper part 12 is small in comparison to that of the lower part 11.

Thelower pedestal part 11 is generally hollow, and in external contour is circular except for the :base, which in this instance is footed. The lower pedestal part 11 flares outwardly in the upward direction to form a continuation of the flaring upper part 12. No discontinuity to eye is apparent, except for the circular line at the separation plane A where a top circular surface 11a of the part 11 opposes the circular undersurface 12a of the part'12.

The pedestal parts 11 and 12 have hubs 18 and 19 by the aid of which a swivel connection between the parts is provided. The hub 18 in the lower part extends upwardly from about the central neck of the pedestal part 11 almost to the plane of the top circular surface 11a. Due to the convergence of the hollow pedestal part, its inner surface merges with the lower end of the hub 18. The'hub 19 in the upper part projects downwardly and terminates above the plane of its circular undersurface 12a. A hearing structure 2%) is interposed between the hubs 18 and 19, whereby the upper pedestal part 12 is supported. The bearing structure 2% in this instance comprises three parts, two apertured washers 21 and 22 and an apeitured retainer 23 (FIG. 5) which mounts a series of roller bearing elements 24. The washers 21 and 22 normally move with their corresponding hubs, and form raceways for the hearing elements 24. The axial dimension of the bearing 2tl is adequate to ensure clearance at the opposed surfaces 11a and 12a.

A shaft 25 confines the pedestal parts 11 and 12 for rotation about the axis 13. For this purpose, the upper end of the shaft 25 is press-fitted or otherwise secured in a downwardly opening recess 26 of the hub 19. The shaft 25 passes through the apertures in the washers 21 and 22 and bearing retainer 23 and through a through bore 27 in the hub 18. A nut 28 on the lower end of the shaft 25 serves as a means for preventing axial separation of the pedestal parts 11 and 12. A hearing structure 29, similar to the bearing structure 20, is interposed between the nut 25 and the lower surface 39 of the hub 18.

In order to provide a return mechanism determining a normal relative angular orientation of the pedestal parts 11 and 12, an actuator or thrust member 31 is provided. The thrust member 31 is mounted on one of the pedestal parts, in this instance, the lower pedestal part 11, and engages an oblique or inclined raceway 32 formed on the other part 12 in surrounding relationship to the hub 19.

The thrust member 31 comprises a sleeve 33 which is slidably accommodated in an outwardly inclined recess 3 extendin inwardly from the upper end of one 35 of three integral supporting ribs for the hub 13. At the upper end of the sleeve 33 is a seat member 36 made of plastic or other material suitable for the purposes hereafter to be described. The sleeve is crimped about the seat member 36 to connect-them together. The upper or projecting end of the seat member 36 has a recess in which a hardened steel ball 37 is retained. The actuator or thrust member 31 is urged outwardly of the recess 3-4 by a compression spring 33, thereby causing the ball 57 to engage the oblique or inclined raceway 32. The spring 38 is seated in the bottom of the recess 34-, and acts directly on the inner end of the seat member 36.

The raceway 32 is formed as the undersurface of a generally circular supporting web 39 radiating from the hub to support the peripheral portions of the part 12.

The ball 37 describes a generally circular or slightly 3 as elliptical path along the raceway '32 as the parts 11 and 12 are moved angularly.

When the trough area of this circular path is engaged by the ball 37 as shown in FIG. 1, maximum expansion of the actuator spring 38 results, this area being farthest removed from the bottom of the recess 34 in which the spring is accommodated. When the crest area, as shown in FIG. 2, is engaged by the ball 37, maximum compression of the spring 38 results, this area being closest to the bottom of the recess 34. The actuator 31 is constantly urged by the spring to occupy a position corresponding to minimum stored energy of the spring 38. Hence, the position of FIG. 1 corresponds to the stable, normal position to which the pedestal parts are returned.

The outward inclination of the recess 34 allows the ball 37 to act at a maximum distance from the axis 13, whereby maximum torque, for a given spring size, is obtained.

In order to provide a very definite centered position, the raceway 32 has a depression 40 (FIG. 4). Due to the depression, an added force will be required to dislodge the ball 37 therefrom. The raceway 32 furthermore has a projection 41 at a position corresponding to maximum compression of the spring 38, that is, at the area of the raceway closest to the pedestal part 11. This projection 41, which is relatively'sharp, prevents the parts 11 and 12 from remaining in a position of unstable equilibrium.

In the form of the invention shown in FIGS. 6 to 9, a similar structure is provided, except that the thrust member 31 is accommodated in the surbase part 51 of the pedestal for engagement with a race insert 52 mounted on the pedestal part 53.

As in the previous form, the pedestal parts are confined for angular movement about a vertical axis. A shaft 54 thus cooperates with interior opposed hubs 55 and 56 of the pedestal parts 53 and 51. The shaft 54- is press fitted in the hub 55 of surbase part and extends downwardly through a bore 57 in the hub 56. The bore 57 is continued through the lower pedestal part 53 whereby the lower end of the shaft 54 is accessible for placement of a nut 58. The nut 58 prevents relative axial movement or separation of the pedestal parts 51 and 53.

A bearing assembly 59 is interposed between the hubs 55 and 56 and determines the normal spacing of the pedestal parts 51 and 53. A bearing assembly 60 is interposed between the nut 58 and the edges about the lower end of the bore 57 so that the nut can rotate with the shaft without loosening.

The thrust member 31 is accommodated in an elongated, downwardly opening recess 61 formed in a lateral projection 62, of the hub 55 (see also FIG. 7). The coil spring 38 urges the thrust member 31 downwardly by reaction against the upper end of the recess 61.

The race insert 52. is made as a single casting, providing the upper raceway 63 having the same functional charaoteristics as the raceway 32 of the previous form. The insert 52 has a central aperture 64 that surrounds the upper end of the hub 56. The insert 52 is substantially of uniform wall thickness and accordingly extends obliquely to the axis of the hub 56 while embracing the hub at its aperture 64.

The insert 52 is held at the top of the hub 56 by engagement with the upper surfaces of reinforcing ribs 65, 66, 67 and 68 that join the hub 56 to the peripheral wall of the pedestal part 53. The upper surfaces of the ribs 6'5 are located at suitable positions 'for cooperation with the obliquely extending insert 52.

In order to lock the insert against rotation while the thrust member moves about the raceway 63, a plurality of depending lugs 69, 70, 71 and 72 integrally formed on the insert 52 fit between the ribs to engage the sides thereof. The lugs 69 and 70, as shown in FIG. 8, are designed to fit in the common arcuate space between the reinforcing ribs 65 and 68 and against the corresponding sides of the ribs 65 and 68. The lugs 71 and 72. similarly fit in the common arcuate space between the reinforcing ribs 66 and 67 and against the sides of the corresponding ribs. The insent '52 is accordingly locked against rotation.

The peripheral wall 73 of the lower pedestal part 53 extends upwardly beyond the hub 56 and in spaced exterior encompassing relationship relative to a substantial portion of the peripheral wall 7 4 of the upper pedestal part 51. Accordingly, the visible line of separation be-' tween the pedestal parts 51 and 53 is located upwardly for substantial concealment by the seat fastened to the surbase part 51.

In FIG. 10, the pedestal parts 51 and 53 are fixed against rotation. The thrust member 31 and race insert 52 are removed. A substitute insert 75 (FIG. 12) is placed about the hub 56 of the base past 53.

Like the race-forming insert 52, the insert 75 is provided with depending lugs 76 for interfitt-ing and interlocking the strengthening ribs 65, 66, 67 and 68. Cylindrical pins 77 and 78 project upwardly and interlock the surbase part 51. Thus, one of the pins 78 extends into the aperture 6i. The other pin 77 extends into a similar recess 79 formed in another laterally projecting part 36 of the hub 54. The surbase part 51, by engagement with the pins 77 and 78, is precluded from rotating relative to the insert 7 5; The lugs '7 6 prevent the insert 75 from rotating relative to the base part 53. Accordingly, all of the parts are locked together, and a non-swivel base is accordingly provided.

. 'In order to provide a swivel base without the return feature, the insert 75 is simply deleted.

The inventor claims:

l. in a pedestal chair: a pedestal including a surbase part and a base part having peripheral walls complementing each other to provide an external contour of the pedestal; means mounting said surbase part for 1-0 rtational movement on said base part about the axis of the pedestal; low friction bearing means between the pedestal parts; means forming on one of said par-ts an endless raceway extending entirely about said axis and being located interiorly of said walls; a thrust member; means carried by the other of said parts guiding said thrust member for movement in a path fixed with respect to the other of the parts, said path intercepting said raceway; spring means urging said thrust rnember to engage said raceway; said thrust member, said guiding means and said spring means being located interiorly of said walls; and means holding said pedestal parts against said bearing means and holding said Walls in closely spaced relationship and preventing relative axial movement of the parts and preventing separation of said walls, thereby concealing said thrust member, said guiding means, said spring means,

and said raceway within said walls; said thrust member permitting endless angular motion between the parts in either angular direction; said raceway being divided into two sloping areas by spaced crest and trough portions; whereby the thrust member creates a turning torque between said parts whenever the thrust member is away trom said trough portion.

2. The combination as set forth in claim 1 in which said raceway forming means is a part axially separable from said pedestal part and operable independently of said bearing means, said raceway forming means and said one pedestal part having means interfitting each other upon axial movement to prevent relative angular movement therebetween; said thrust member holding said raceway forming means against axial separation from said one pedestal part, said raceway forming means being otherwise unattached to said one pedestal part.

3. The combination as set forth in claim 1 in which said raceway forming means is a part axially separable from said pedestal part and operable independently of said bearing means, said raceway forming means and said one pedestal part having means interfitting each other upon axial movement to prevent relative angular movement therebetween; said thrust member holding said raceway forming means against axial separation from said one pedestal part; said raceway forming means being otherwise unattached to said one pedestal part; said guiding means including an elongated recess, the thrust member fitting the recess; and a replacement insert tor the raceway forming means and the thrust member and fitting the pedestal parts in substitution thereof for locking said pedestal parts against rotation.

4. In a pedestal chair as set forth in claim 1, said thrust member including a ball bearing adapted to engage said raceway and move therealong.

5. In a pedestal structure: a pair of complementary hollow pedestal parts, each made as a unitary casting, one of the parts being a base part and the other of the parts being a surbase part; said parts having peripheral circularly extending walls separated at a horizontal plane, the external surface contour of the walls of said surbase part forming a continuation of the external surface contour of said base part; said surbase part having a hub and a web integrally joining the hub to the peripheral walls of the surbase part; said web being located substantially in a plane that is inclined to said horizontal plane; said web providing a substantially circularly extending raceway surrounding the hub at a place adjacent the peripheral walls of said surbase part, said raceway being opposed to said base part; a thrust bearing interposed between said hub and said base part and defining a slight separation between said parts at their said circular peripheral walls; said bearing permitting angular movement of said surbase part about the axis of said circular peripheral walls; a shaft fitting the hub and said base part and located at the axis of the said circular peripheral walls, and confining said pedestal parts for rotation about said axis; detachable means engaging the shaft and holding the said pedestal parts in a fixed spaced relationship at said horizontal plane; said base pedestal part having a bore opening at a place opposed to said raceway and within the peripheral circular walls of said base part; a sleeve guided in the bore; a ball seat carried at the outer end of the sleeve; a ball in the ball seat; a compression spring in the bottom of the bore and guided by said sleeve to engage said ball seat to urge said ball into engagement with said raceway; said sleeve, ball seat, ball and spring being freely removable when said pedestal par-ts are separated upon detachment of said detachable means.

6. In a pedestal structure: a pair of complementary hollow pedestal parts, each made as a unitary casting, one of the parts being a base part and the other of the parts being a surbase part; said parts having peripheral annular walls having portions opposed to and separated from each other, the external surface contour of the walls of said surbase part forming a continuation of the external surface contour of said base part; said surbase part having a hub and a web integrally joining the hub to the peripheral walls of the surbase part; said web being located substantially in a plane that is inclined to said horizontal plane; said web providing a substantially circularly extending raceway surrounding the hub at a place adjacent the peripheral walls of said surbase part, said raceway bein-g opposed to said base part; a thrust bear ing interposed between said hub and said base part and defining a slight separation between said parts at their said circular peripheral walls; said bearing permitting angular movement of said surbase part about the axis of said circular peripheral walls; a shaft fitting the hub and said base part and located at the axis of the said circular peripheral walls, and confining said pedestal parts for rotation about said axis; detachable means engaging the shaft and holding the said pedestal parts in a fixed spaced relationship at said horizontal plane; said base pedestal part having a bore opening at a place opposed to said raceway and within the peripheral circular walls of said base part; a sleeve guided in the bore; a ball seat carried at the outer end of the sleeve; a ball in the ball seat; a compression spring in thebottom of the bore and guided by said sleeve to engage said ball seat to urge said ball into engagement with said raceway; said sleeve, ball seat, ball and spring being freely removable when said pedestal parts are separated upon detachment of said detachable means.

References Cited in the file of this patent UNITED STATES PATENTS 1,299,810 T0016 Apr. 8, 1919 1,695,725 Wolfe Dec. 18, 1928 1,897,676 Ries Feb. 14, 1933 2,217,943 Carlson Oct. 15, 1940 

1. IN A PEDESTAL CHAIR: A PEDESTAL INCLUDING A SURBASE PART AND A BASE PART HAVING PERIPHERAL WALLS COMPLEMENTING EACH OTHER TO PROVIDE AN EXTERNAL CONTOUR OF THE PEDESTAL; MEANS MOUNTING SAID SURBASE PART FOR ROTATIONAL MOVEMENT ON SAID BASE PART ABOUT THE AXIS OF THE PEDESTAL; LOW FRICTION BEARING MEANS BETWEEN THE PEDESTAL PARTS; MEANS FORMING ON ONE OF SAID PARTS AN ENDLESS RACEWAY EXTENDING ENTIRELY ABOUT SAID AXIS AND BEING LOCATED INTERIORLY OF SAID WALLS; A THRUST MEMBER, MEANS CARRIED BY THE OTHER OF SAID PARTS GUIDING SAID THRUST MEMBER FOR MOVEMENT IN A PATH FIXED WITH RESPECT TO THE OTHER OF THE PARTS, SAID PATH INTERCEPTING SAID RACEWAY; SPRING MEANS URGING SAID THRUST MEMBER TO ENGAGE SAID RACEWAY; SAID THRUST MEMBER, SAID GUIDING MEANS AND SAID SPRING MEANS BEING LOCATED INTERIORLY OF SAID WALLS; AND MEANS HOLDING SAID PEDESTAL PARTS AGAINST SAID BEARING MEANS AND HOLDING SAID WALLS IN CLOSELY SPACED RELATIONSHIP AND PREVENTING RELATIVE AXIAL MOVEMENT OF THE PARTS AND PREVENTING SEPARATION OF SAID WALLS, THEREBY CONCEALING SAID THRUST MEMBER, SAID GUIDING MEANS, SAID SPRING MEANS, AND SAID RACEWAY WITHIN SAID WALLS; SAID THRUST MEMBER PERMITTING ENDLESS ANGULAR MOTION BETWEEN THE PARTS IN EITHER ANGULAR DIRECTION; SAID RACEWAY BEING DIVIDED INTO TWO SLOPING AREAS BY SPACED CREST TROUGH PORTIONS; WHEREBY THE THRUST MEMBER CREATES A TURNING TORQUE BETWEEN SAID PARTS WHENEVER THE THRUST MEMBER IS AWAY FROM SAID TROUGH PORTION. 